1. Field of the Invention
The present invention relates to hydraulically operated diverter tools used in diverting pump-down oil tool equipment and, more particularly, relates to hydraulically operated diverter tools supported within a sidepocket mandrel of a pipeline installed and removed therefrom using standard oil field equipment.
2. Description of the Prior Art
Within the last few years, offshore oil and gas production has continued to expand into deeper water depths in attempts to satisfy the world oil demands. To handle the environmental constraints imposed by the increased depths more efficiently, a Subsea Production System (SPS) as disclosed in Burkhardt et al, U.S. Pat. No. 3,777,812, has been developed to produce oil and gas directly on the seabed. The SPS is designed to operate in a submerged mode on the seabed without the need of a large offshore production platform. As discussed in Burkhardt, the SPS includes a complicated network of production lines, gas injection lines, waterflood lines and through-the-flowline (TFL) maintenance or service lines (column 3, line 29 et seq.). The TFL service lines are used to introduce pump-down tools (PDT), also known as TFL tools, into the oil wells for maintenance and related activity associated with the completion of a well.
Many types of diverters employ a gate or flapper to deflect a TFL tool from a TFL service line into the production line of a well (see Weber et al, U.S. Pat. Nos. 3,866,628, Fowler, 3,472,317 and Johnson, 3,139,932). That section of pipe where the TFL service lines and production lines branch off is frequently termed a wye-section. The use of diverter tools with respect to the SPS is further discussed in Burkhardt at column 3, lines 17 et seq.
One type of TFL diverter which is remotely serviceable is described in Childers et al, U.S. Pat. No. 3,881,516. A portion of the hydraulically operated diverter disclosed therein is serviceable from outside the pipeline by means of a subsea manipulator such as that discussed by Burkhardt at column 4, line 24 et seq. Only the hydraulic operator assembly, however, is removable from the pipeline and, therefore, capable of being remotely replaced or repaired at the water surface. The diverter body and paddle are not removable. Another type of hydraulically operated TFL diverter known as a dual reciprocating diverter is discussed in a paper by Drouin and Fowler entitled "Diverters for TFL Tools" presented at the ASME Petroleum Mechanical Engineering Conference, Tulsa, Oklahoma, September, 1969. The diverter disclosed therein was improved upon by Childers' U.S. Pat. No. 3,881,516 (see Childers, Patent 3,881,516, column 1, lines 20-28).
An evaluation of the hydraulically operated diverters available in industry has shown that due to the repeated servicing requirements of not only the actual operating mechanism but also the flapper or paddle and the associated linkage which pivots the flapper, a need exists for an easily serviceable diverter which can be installed and retrieved directly from the maintenance line in its entirety using such standard down-hole oil field equipment as a kickover tool. In this manner, the need for an expensive subsea manipulator which operates outside the production lines to remotely remove the hydraulic operator of a diverter is minimized. Indeed, if the manipulator was used solely to replace the hydraulic operator of a diverter as disclosed in Childers' Patent 3,881,516, the need for the manipulator for this task would be entirely eliminated if the hydraulic operator was retrievable from inside the maintenance line using standard oil field equipment. The use of standard equipment for servicing the diverter is preferable since such tools are readily available and highly reliable.